Stage changes

The staging area lets you decide exactly what the next commit will contain.

Stage one file with:

git add README.md

Staging is not saving the file. Your editor already did that. git add copies the file’s current content into the index.

Verify the staged change:

git status
git diff --staged

If you edit README.md again, the new edit remains in the working tree. The index still contains the version you staged earlier. Run both commands:

git diff
git diff --staged

This is useful when one file contains two unrelated changes. You can stage only selected parts with git add -p, review each hunk, and leave the rest for another commit.

Avoid git add . until you have checked git status. It is easy to include generated files or unrelated edits.

Exercise: make two edits to one file. Stage it after the first edit, make the second edit, then predict which content the next commit would record.